梯度密度聚氨酯泡沫塑料的制备及性能研究
作者：赵春玉
院校:北京化工大学
关键字:密度分布;梯度;聚氨酯;泡沫体
学位：硕士
专业:应用化学
摘要:
梯度密度聚氨酯泡沫塑料具有高密度、结实光滑而坚韧的外表皮和低密度泡沫芯。本文研究了梯度密度聚氨酯泡沫塑料的制造方法、配方和工艺条件;制品的密度分布和力学性能;以及主要原料和反应体系的流变性能。 为了降低硬质聚氨酯泡沫塑料的密度,同时保留原来密度下的性能,本文制备了梯度密度聚氨酯泡沫塑料,并对其性能进行了研究。低密度泡沫芯使它保留重量轻、导热系数小等优点,高密度表皮使泡沫体具有良好的强度与硬度。由于聚氨酯泡沫体密度呈梯度分布,其性能优于均匀密度泡沫塑料,且重量轻,加工成本低廉,结构可选择范围广,设计灵活,因此具有广阔的应用前景和良好的经济效益。 采用模塑成型和嵌入成型两种方法,通过改变体积填充系数、质量填充系数和芯体尺寸,制备了梯度密度聚氨酯泡沫塑料。 研究了梯度密度聚氨酯泡沫塑料的密度分布,测试了制品的表皮硬度、压缩强度、冲击强度、弯曲强度,深入研究了体积填充系数、质量填充系数以及夹芯结构对梯度密度聚氨酯泡沫塑料性能的影响。 研究了发泡剂用量对聚氨酯泡沫主反应原料粘度的影响,以及反应过程中的化学流变性能。根据反应特点和流变性质把反应过程划分为四个阶段:反应初期、反应加速期、凝胶阶段和固化阶段,研究了化学反应对流变性能的影响。
Abstract:
Gradient-density polyurethane foam has smooth,high-density,tough and tensile external skin and low-density core. This paper studied the compound formulations and processing conditions in making gradient-density polyurethane foam; the density distribution and mechanical properties of the products; the rheology of the main reactants and the reaction system. In order to reduce the density of rigid polyurethane foam and preserve its original performance synchronously, gradient-density polyurethane foam was manufactured. Low-density core makes it have the advantage of light mass and small heat conduction coefficient. High-density skin makes it have fine rigidity and intensity. Due to its density distribution, the properties of gradient-density polyurethane foam is superior to those of even-density polyurethane foam. Gradient-density PUF was produced in two ways : mould shaping and embed shaping, through changing volume filling coefficient, mass filling coefficient, and the size of foam core. This paper investigated the density distribution of gradient-density polyurethane foam and tested its mechanical properties, including surface rigidity, compressive strength, impact strength, flexural strength. The influence of filling coefficient and core size on mechnical properties are deeply investigated. This paper studied the influence of blowing agent dosage on the main reactant of PUF, and the chemorheology in reaction process. According to reaction characteristics and rheology, the reaction process was divided into four parts: reaction initial stage, reaction accelerates stage, gel stage, and cure stage.